package com.ruoyi.common.utils.file;

import java.io.*;
import java.net.URLEncoder;
import java.nio.channels.FileChannel;
import java.nio.charset.StandardCharsets;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.collections4.CollectionUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.ArrayUtils;
import com.ruoyi.common.config.RuoYiConfig;
import com.ruoyi.common.utils.DateUtils;
import com.ruoyi.common.utils.StringUtils;
import com.ruoyi.common.utils.uuid.IdUtils;
import org.apache.commons.io.FilenameUtils;

/**
 * 文件处理工具类
 *
 * @author ruoyi
 */
public class FileUtils
{
    // 下面这个函数用于将字节数组换成成16进制的字符串
    private static final char[] DIGITS_LOWER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
    public static String FILENAME_PATTERN = "[a-zA-Z0-9_\\-\\|\\.\\u4e00-\\u9fa5]+";

    /**
     * 输出指定文件的byte数组
     *
     * @param filePath 文件路径
     * @param os 输出流
     * @return
     */
    public static void writeBytes(String filePath, OutputStream os) throws IOException
    {
        FileInputStream fis = null;
        try
        {
            File file = new File(filePath);
            if (!file.exists())
            {
                throw new FileNotFoundException(filePath);
            }
            fis = new FileInputStream(file);
            byte[] b = new byte[1024];
            int length;
            while ((length = fis.read(b)) > 0)
            {
                os.write(b, 0, length);
            }
        }
        catch (IOException e)
        {
            throw e;
        }
        finally
        {
            IOUtils.close(os);
            IOUtils.close(fis);
        }
    }

    /**
     * 写数据到文件中
     *
     * @param data 数据
     * @return 目标文件
     * @throws IOException IO异常
     */
    public static String writeImportBytes(byte[] data) throws IOException
    {
        return writeBytes(data, RuoYiConfig.getImportPath());
    }

    /**
     * 写数据到文件中
     *
     * @param data 数据
     * @param uploadDir 目标文件
     * @return 目标文件
     * @throws IOException IO异常
     */
    public static String writeBytes(byte[] data, String uploadDir) throws IOException
    {
        FileOutputStream fos = null;
        String pathName = "";
        try
        {
            String extension = getFileExtendName(data);
            pathName = DateUtils.datePath() + "/" + IdUtils.fastUUID() + "." + extension;
            File file = FileUploadUtils.getAbsoluteFile(uploadDir, pathName);
            fos = new FileOutputStream(file);
            fos.write(data);
        }
        finally
        {
            IOUtils.close(fos);
        }
        return FileUploadUtils.getPathFileName(uploadDir, pathName);
    }

    /**
     * 删除文件
     *
     * @param filePath 文件
     * @return
     */
    public static boolean deleteFile(String filePath)
    {
        boolean flag = false;
        File file = new File(filePath);
        // 路径为文件且不为空则进行删除
        if (file.isFile() && file.exists())
        {
            flag = file.delete();
        }
        return flag;
    }

    /**
     * 文件名称验证
     *
     * @param filename 文件名称
     * @return true 正常 false 非法
     */
    public static boolean isValidFilename(String filename)
    {
        return filename.matches(FILENAME_PATTERN);
    }

    /**
     * 检查文件是否可下载
     *
     * @param resource 需要下载的文件
     * @return true 正常 false 非法
     */
    public static boolean checkAllowDownload(String resource)
    {
        // 禁止目录上跳级别
        if (StringUtils.contains(resource, ".."))
        {
            return false;
        }

        // 检查允许下载的文件规则
        if (ArrayUtils.contains(MimeTypeUtils.DEFAULT_ALLOWED_EXTENSION, FileTypeUtils.getFileType(resource)))
        {
            return true;
        }

        // 不在允许下载的文件规则
        return false;
    }

    /**
     * 下载文件名重新编码
     *
     * @param request 请求对象
     * @param fileName 文件名
     * @return 编码后的文件名
     */
    public static String setFileDownloadHeader(HttpServletRequest request, String fileName) throws UnsupportedEncodingException
    {
        final String agent = request.getHeader("USER-AGENT");
        String filename = fileName;
        if (agent.contains("MSIE"))
        {
            // IE浏览器
            filename = URLEncoder.encode(filename, "utf-8");
            filename = filename.replace("+", " ");
        }
        else if (agent.contains("Firefox"))
        {
            // 火狐浏览器
            filename = new String(fileName.getBytes(), "ISO8859-1");
        }
        else if (agent.contains("Chrome"))
        {
            // google浏览器
            filename = URLEncoder.encode(filename, "utf-8");
        }
        else
        {
            // 其它浏览器
            filename = URLEncoder.encode(filename, "utf-8");
        }
        return filename;
    }

    /**
     * 下载文件名重新编码
     *
     * @param response 响应对象
     * @param realFileName 真实文件名
     */
    public static void setAttachmentResponseHeader(HttpServletResponse response, String realFileName) throws UnsupportedEncodingException
    {
        String percentEncodedFileName = percentEncode(realFileName);

        StringBuilder contentDispositionValue = new StringBuilder();
        contentDispositionValue.append("attachment; filename=")
                .append(percentEncodedFileName)
                .append(";")
                .append("filename*=")
                .append("utf-8''")
                .append(percentEncodedFileName);

        response.addHeader("Access-Control-Expose-Headers", "Content-Disposition,download-filename");
        response.setHeader("Content-disposition", contentDispositionValue.toString());
        response.setHeader("download-filename", percentEncodedFileName);
    }

    /**
     * 百分号编码工具方法
     *
     * @param s 需要百分号编码的字符串
     * @return 百分号编码后的字符串
     */
    public static String percentEncode(String s) throws UnsupportedEncodingException
    {
        String encode = URLEncoder.encode(s, StandardCharsets.UTF_8.toString());
        return encode.replaceAll("\\+", "%20");
    }

    /**
     * 获取图像后缀
     *
     * @param photoByte 图像数据
     * @return 后缀名
     */
    public static String getFileExtendName(byte[] photoByte)
    {
        String strFileExtendName = "jpg";
        if ((photoByte[0] == 71) && (photoByte[1] == 73) && (photoByte[2] == 70) && (photoByte[3] == 56)
                && ((photoByte[4] == 55) || (photoByte[4] == 57)) && (photoByte[5] == 97))
        {
            strFileExtendName = "gif";
        }
        else if ((photoByte[6] == 74) && (photoByte[7] == 70) && (photoByte[8] == 73) && (photoByte[9] == 70))
        {
            strFileExtendName = "jpg";
        }
        else if ((photoByte[0] == 66) && (photoByte[1] == 77))
        {
            strFileExtendName = "bmp";
        }
        else if ((photoByte[1] == 80) && (photoByte[2] == 78) && (photoByte[3] == 71))
        {
            strFileExtendName = "png";
        }
        return strFileExtendName;
    }

    /**
     * 获取文件名称 /profile/upload/2022/04/16/ruoyi.png -- ruoyi.png
     *
     * @param fileName 路径名称
     * @return 没有文件路径的名称
     */
    public static String getName(String fileName)
    {
        if (fileName == null)
        {
            return null;
        }
        int lastUnixPos = fileName.lastIndexOf('/');
        int lastWindowsPos = fileName.lastIndexOf('\\');
        int index = Math.max(lastUnixPos, lastWindowsPos);
        return fileName.substring(index + 1);
    }

    /**
     * 获取不带后缀文件名称 /profile/upload/2022/04/16/ruoyi.png -- ruoyi
     *
     * @param fileName 路径名称
     * @return 没有文件路径和后缀的名称
     */
    public static String getNameNotSuffix(String fileName)
    {
        if (fileName == null)
        {
            return null;
        }
        String baseName = FilenameUtils.getBaseName(fileName);
        return baseName;
    }

    public static String getFileMD5(File file) throws Exception {
        // 缓冲区大小（这个可以抽出一个参数）
        int bufferSize = 256 * 1024;
        byte[] buffer = new byte[bufferSize];
        FileInputStream fileInputStream = null;
        DigestInputStream digestInputStream = null;
        try {
            // 拿到一个MD5转换器（同样，这里可以换成SHA1）MD5,SHA1
            MessageDigest messageDigest = MessageDigest.getInstance("SHA1");
            // 使用DigestInputStream
            fileInputStream = new FileInputStream(file);
            digestInputStream = new DigestInputStream(fileInputStream, messageDigest);
            // read的过程中进行MD5处理，直到读完文件
            while (digestInputStream.read(buffer) != -1) {
            }
            // 获取最终的MessageDigest
            messageDigest = digestInputStream.getMessageDigest();
            // 拿到结果，也是字节数组，包含16个元素
            byte[] resultByteArray = messageDigest.digest();
            // 同样，把字节数组转换成字符串
            return byteArrayToHex(resultByteArray);
        } finally {
            if (digestInputStream != null) {
                try {
                    digestInputStream.close();
                } catch (Exception e) {
                }
            }

            if (fileInputStream != null) {
                try {
                    fileInputStream.close();
                } catch (Exception e) {
                }
            }

        }
    }

    public static String byteArrayToHex(byte[] bytes) {
        final int len = bytes.length;
        final char[] out = new char[len << 1];
        for (int i = 0, j = 0; i < len; i++) {
            out[j++] = DIGITS_LOWER[(0xF0 & bytes[i]) >>> 4];
            out[j++] = DIGITS_LOWER[0x0F & bytes[i]];
        }
        return new String(out);
    }

    /**
     * 文件切分
     *
     * @param originFilePath 大文件地址
     * @param splitFileSize  切分大小
     * @return 切分后生成的文件集合
     * @throws IOException
     */
    public static List<String> split(String originFilePath, int splitFileSize) throws IOException {
        File file = new File(originFilePath);
        long left = file.length();
        int count = (int) Math.ceil(left / (double) splitFileSize);
        int countLen = String.valueOf(count).length();
        List<String> splitFilePaths = new ArrayList<>(count);
        RandomAccessFile source = new RandomAccessFile(file, "r");
        FileChannel srcChannel = source.getChannel();
        long start = 0;
        for (int i = 0; i < count; i++) {
            String splitFilePath = file.getAbsolutePath() + "." + StringUtils.leftPad(String.valueOf((i + 1)), countLen, '0') + ".part";
            try (FileOutputStream fos = new FileOutputStream(splitFilePath);
                 FileChannel destChannel = fos.getChannel()) {
                srcChannel.transferTo(start, splitFileSize, destChannel);
                start += splitFileSize;
                splitFilePaths.add(splitFilePath);
            }
        }
        return splitFilePaths;
    }

    /**
     * 文件合并
     *
     * @param splitFilePaths 被切分的文件地址
     * @param mergeFilePath  生成文件地址
     * @throws IOException
     */
    public static void merge(List<String> splitFilePaths, String mergeFilePath) throws IOException {
        if (StringUtils.isBlank(mergeFilePath) || CollectionUtils.isEmpty(splitFilePaths)) {
            return;
        }
        RandomAccessFile file = new RandomAccessFile(mergeFilePath, "rw");
        FileChannel channel = file.getChannel();
        long lastSplitFileSize = 0;
        for (String splitFilePath : splitFilePaths) {
            try (FileInputStream fs = new FileInputStream(splitFilePath);
                 FileChannel srcChannel = fs.getChannel()) {
                long size = srcChannel.size();
                channel.transferFrom(srcChannel, lastSplitFileSize, size);
                lastSplitFileSize += size;
            }
        }
        for (String splitFilePath : splitFilePaths) {
            File file1 = new File(splitFilePath);
            file1.delete();
        }
    }


    public static StringBuffer readLine(String filePath) throws IOException {
        StringBuffer buffer = new StringBuffer();
        File file = new File(filePath);
        BufferedReader reader = null;
        String tempString = null;
        try {
            reader = new BufferedReader(new FileReader(file));
            while ((tempString = reader.readLine()) != null) {
                buffer.append(tempString);
            }
            reader.close();
        } finally {
            if (reader != null) {
                reader.close();
            }
        }
        return buffer;
    }

    public static StringBuffer readChars(String filePath) throws IOException {
        StringBuffer buffer = new StringBuffer();
        File file = new File(filePath);
        InputStream in = null;
        byte[] tempByte = new byte[1024];
        int byteread = 0;

        try {
            System.out.println("以字节为单位读取文件内容，一次读多个字节：");
            in = new FileInputStream(file);
            while ((byteread = in.read(tempByte)) != -1) {
                String str = new String(tempByte, 0, byteread);
                buffer.append(str);
            }
        } finally {
            if (in != null) {
                in.close();
            }
        }
        return buffer;
    }


}
